As marijuana prices begin to fall and electrical prices continue to skyrocket, the old-school technique of light deprivation greenhouses has again become madly popular across this pot-loving country. While light deprivation (A.K.A. “light-dep”) techniques have been utilized with other crops throughout mankind's agricultural history, there are many within the marijuana cultivation world that have never heard of this money-saving, cycle increasing technique.
For those trying to wrap their head around this ancient concept, light-dep is a technique of artificially reducing the plant's light cycle in order to force a vegetating plant into flowering. This is done by systematically covering the greenhouse to block out sunlight – thereby forcing the plants into flowering early due to their deprived photo period.
For marijuana growers, a prolonged photoperiod is of the utmost importance for maintaining their plants' critical flowering stage, a precarious phase for the plants bud production that requires a maximum of 12 hours of light. For the absent-minded cultivator this is a dangerous time. Once a light-dep grow is initiated there is no going back. Marijuana plants will not flower with more than 12 hours of light a day. So preoccupied cultivators who forget to cover their greenhouse at the right time could potentially risk their plants reverting back into their vegetative cycle. While labor-intensive, this cultivation technique is critical for marijuana cultivators who require a consistent and timely harvest.
In the agricultural world, much like other industries, time = money. Understanding this simple fact, many of today's medical marijuana growers are utilizing light-dep as a means of increasing their annual harvests, particularly during the summer months. Experienced cultivators looking to maximize their number of harvests per year are now covering their outside greenhouses with opaque tarps, restricting the daylight the plants receive to no more than 12 hours a day. By doing so, greenhouse cultivators can manipulate their crops to produce flower earlier and more often than the traditional Sun & Soil cultivator – increasing their number of annual harvests exponentially.
As is almost always the case, there are several ways to accomplish this task. For those cultivators limited to a smaller greenhouse, making it light-dep is as simple as pulling a dark colored opaque tarp over the greenhouse after no more than 12 hours of light; remaining consistent on a daily basis.
For those growers blessed with a more commercial operation, industrial sized shades are usually installed with a programmable timer that automatically covers their greenhouse at the same time every day until harvest. While not cheap, the latter method is obviously the way to go, even for those growers restricted to smaller greenhouses. Automatic timers tend to eliminate the human error factor during the money making time of flower production. Timing, consistency and commitment are important virtues with this technique. Even the smallest amount of sunlight hitting a marijuana plants after they've begun the light-dep process can have a disastrous effect – causing them to revert back to their vegetative state. This unfortunate type of confusion for the plants has been shown to reduce their rapid progression and vitality, and could potentially force them to turn hermaphrodite.
While the potential drawbacks are there, the ancient technique of agricultural light deprivation is helping greenhouse growers increase today's harvests by using nothing more than natural sunlight and an elevated sense of timing.